A model for a laser with dual-pass pumping is established, and an equation expressing the mode matching for this structure is presented. Through the numerical analysis of this equation, under the conditions of weak-ab...A model for a laser with dual-pass pumping is established, and an equation expressing the mode matching for this structure is presented. Through the numerical analysis of this equation, under the conditions of weak-absorption and effective absorption efficiency, the optimum radius of the pump beam waist as well as the optimum location is fitted to simple formulas, considering the quality of the pump beam, absorption coefficient, and beam waist of the cavity mode.Using these formulas, the laser with dual-pass pumping could be optimized to obtain a high slope efficiency. To test the utility of this model, an Nd：YVO4 laser with dual-pass pumping and weak-absorption was built and optimized according to the results of the calculation. A good agreement between the results of the calculations and the experiment verified the model and the numerical analysis.展开更多
We propose a novel non-contact rotational sensor based on a fiber Bragg grating(FBG) packaged in a core of a magnetic head, which converts the introduced strain from the circular magnetic railings ruler into the rotat...We propose a novel non-contact rotational sensor based on a fiber Bragg grating(FBG) packaged in a core of a magnetic head, which converts the introduced strain from the circular magnetic railings ruler into the rotational information. A mathematical model is built for processing the data obtained by an interrogator, and the accuracy and resolution of the measurements are analyzed by altering the radius and period of the circular magnetic railings ruler, as well as the dimension of the sensor. The experimental results show that it is in good accordance with the theoretical analysis on rotational angle, and the fitting results indicate that the results obtained from the rotational sensor match very well with the real rotational velocity with a linearity of 0.998 and a standard error of about 0.01.展开更多
文摘A model for a laser with dual-pass pumping is established, and an equation expressing the mode matching for this structure is presented. Through the numerical analysis of this equation, under the conditions of weak-absorption and effective absorption efficiency, the optimum radius of the pump beam waist as well as the optimum location is fitted to simple formulas, considering the quality of the pump beam, absorption coefficient, and beam waist of the cavity mode.Using these formulas, the laser with dual-pass pumping could be optimized to obtain a high slope efficiency. To test the utility of this model, an Nd：YVO4 laser with dual-pass pumping and weak-absorption was built and optimized according to the results of the calculation. A good agreement between the results of the calculations and the experiment verified the model and the numerical analysis.
基金supported by the Program for Cheung Kong Scholars and Innovative Research Team in University(No.IRT1212)the Project Plan of Beijing Municipal Science and Technology Commission(No.Z151100003615010)the Project Plan of Beijing Municipal Education Commission for Enhancing the Innovation Capability in 2015(No.TJSHG201510772016)
文摘We propose a novel non-contact rotational sensor based on a fiber Bragg grating(FBG) packaged in a core of a magnetic head, which converts the introduced strain from the circular magnetic railings ruler into the rotational information. A mathematical model is built for processing the data obtained by an interrogator, and the accuracy and resolution of the measurements are analyzed by altering the radius and period of the circular magnetic railings ruler, as well as the dimension of the sensor. The experimental results show that it is in good accordance with the theoretical analysis on rotational angle, and the fitting results indicate that the results obtained from the rotational sensor match very well with the real rotational velocity with a linearity of 0.998 and a standard error of about 0.01.
